Medical patient access devices and access systems allow access to the interior of the patient (such as the vascular system) to deliver a fluid or a pharmaceutical. However, the movement of potentially deadly microorganisms into patient's interior through such access devices and systems has long been a major problem. Bacteria and yeast may gain entry into a patient's vascular system from access ports during the connection of the port to deliver the fluid or pharmaceutical. In fact each access occurrence into an access portal is associated with at least some risk of comprising a “Microorganism Transmitting Event” (MTE). The bacterial or yeast bolus associated with a MTE can comprise a single organism or greater than 1000 organisms. While most MTEs are without consequence, each MTE poses a risk of causing clinical bacteremia which is associated with severe morbidity, increased hospital expense and/or death. The risk of each MTE is related to the vulnerability of the patient and the pathogenicity and sensitivity of the organism transmitted. Factors which greatly amplify the risk posed by a given MTE are a low WBC count, the presence of prosthetic heart valves or joints, and malnutrition, to name a few. Regardless of the vulnerability of the patient, once clinical bacteremia is established, the death rate is relatively high. Microorganisms are becoming more resistant to antibiotics and patients are often living longer with more prosthetic components and therefore the risk posed by MTEs to patients will likely continue to increase over the next few decades.
Throughout the sequence of procedures associated with an access event there are many risks of contact or droplet nuclei contamination which can contribute to MTEs. Contamination can occur during drug mixing, attachment of a cannula, and insertion into the access portal. Because the access procedure is so common and simple, the risk associated with entry into fluid connection with a patient's vascular system has often been overlooked. Presently the risk to hospitals and patients is a substantial function of diligence of the employee performing the accesses and this diligence is largely uncontrollable. When substantial morbid and mortal risk in association with a high number of routine procedures is defined as a primary function of the diligence of a heterogeneous population of employees, a substantial degree of unnecessary injury to patients will inevitably result The present inventor contends that it is unacceptable for hospitals to perform hundreds of thousands of accesses to patient's vascular system without controlling all of the controllable risks associated with the access procedure.
It is the purpose of the present invention to provide a system and method which allows control of the risk along that all portions of the medication mixing delivery process such that drug mixing can be performed at the bedside within a predictably sterile enclosure and patient protecting components such as the biocidal septum and cannula system with or without a antiseptic cover are used so that substantially all of the controllable risks are controlled.
One purpose of the present invention is to reduce global morbidity and mortality related to access worldwide by reducing the contamination risk associated with drug mixing, reduce the risk associated with each access, and finally to reduce the number of accesses themselves.
It is important to understand the dynamics of access related transmission events. For this purpose several useful terms will be introduced. The present inventor defines the “MTE Magnitude” as the number of transmitted organisms associated with a given MTE. The peak, the variability and distribution, and the aggregate MTE Magnitude values (such as the mean MTE Magnitude per 100 access events) are all relevant. The present inventor defines the “MTE %” as the percentage of access events which are associated with MTEs. Because access devices differ in structure and function, each access device type differs both with respect to the MTE % and at least one value indicative of the MTE Magnitude. The risk of clinical bacteremia and death due to a MTE is a direct function of 3 primary factors. The MTE Magnitude, the pathogenicity of the organisms transmitted, and the patient's state of vulnerability. Finally, the risk of severe sepsis induced morbidity and/or death due to an access device is a direct function 4 primary factors, the MTE Magnitude, the MTE %., the pathogenicity of the organisms transmitted, and the patient's state of vulnerability. The first two of those factors are exquisitely dependent on the design of the access device.
Given the complexity defining the risks associated with a given access event, the addition of new uncontrolled risk associated with a less than diligent worker in the performance of a diligence dependent access procedure is unacceptable. Since worker diligence can never be reasonably assured, it is one of the purposes of the present invention to provide a much more “diligence independent access procedure”.
In many environments and medical settings cleansing immediately prior to access is not reliably performed, therefore even if it is possible to comprehensively clean an access device and thereby achieve low the MTE % and MTE Magnitude values for a given device in a carefully performed clinical trail, this approach would not reflect the likely real world impact of that access device on global mortality. In addition the effect of even a single missed cleaning event prior to access may have a greater impact on certain access device types. While a missed cleaning event prior to access may have little effect on one device type (other than perhaps to cause a single MTE event to occur during the access which occurred without the cleansing), the same single missed cleaning event may severely contaminate the interior of another device type. For example, the interstitial dead spaces of open piston valves, which is juxtaposed the fluid opening, are not accessible to cleaning. For this reason, even a single event of failure to cleanse the access surface of an open piston valve prior an access event may contaminate the incubating interstitial spaces of an open piston valve early in its use and therefore may potentially cause a rapid rise in both MTE % and MTE Magnitude as the organisms incubate inside the valve over the next 72 hours (long after the initial uncleansed access occurred). The present inventor designates this feature of some access devices as “access induced, irreversible incubation”. Conventional access device designs in wide use today which exhibit a functional propensity for irreversible incubation will not stand the test of time.
In the real world a mix of cleansed and uncleansed accesses commonly occur. Since cleansing is not universally practiced, a combination of both the cleansed and uncleansed MTE % and MTE Magnitude values reflect the real word risk of morbidity and death related to access. In addition the effect of early internal contamination on internal incubation and rising MTE % and MTE Magnitude should be evaluated if the true risk of a given device is to be reasonably assessed.
The present inventor proposes that the annual number of deaths worldwide associated with access devices is given by formula 1. The implications of this simple formula are profound and formula 1 should be considered carefully by every designer of access devices.D=A1(R1)+A2(R2) . . . +An(Rn)  1.Where:                D=the number of sepsis deaths per year due to access events        A1=the number of accesses events per year for device 1        R1=the mean risk of death per access event for device 1        n=the number of different access devices in the worldwide marketR1 is a direct function at least one MTE magnitude value for access device 1. Of course the value R for any access device cannot be known with the evidence available today and even for the most dangerous access devices, R will be extremely small. However, worldwide millions of access events are performed every day. For this reason very small difference in MTE % and/or MTE Magnitude between widely deployed devices can translate into major differences in access device related mortality. Perhaps the most subtle implications of formula 1 is that minor design features which subtly favor microorganism transmission or even a modestly inferior design type with exhibits the propensity for irreversible incubation may have a major impact on the access related death rate worldwide. Also because any R is vastly amplified in patients with low WBC or when the organism is highly pathogenic and resistant (such as Vancomycin Resistant Staphlococcus Aureus), a modestly inferior design may appear quite safe in one population but be highly dangerous to other populations.        
The above relationship clearly shows that the global death rate associated with access devices can be reduced by reducing the number of access events or by developing new devices with a lower MTE % and MTE Magnitude values especially if these are low for both cleansed and uncleansed accesses. An access device which has low MTE % and MTE Magnitude values in both the cleansed and uncleansed state is described by the present inventor as comprising an “anti-infective access device”. It is the one purpose of the present invention to reduce the global death rate related to access events by providing an anti-infective access device which achieves; a reduction in number of access events, a reduction in the MTE % and MTE Magnitude, less dependency on cleansing, and high resistance to irreversible contamination and incubation.
According to one aspect of the present invention an access system is provided which does not protect or incubate microorganisms in exposed regions juxtaposed the fluid path. With devices which lack this feature, such as the open piston valves (like the Clave), bacteria (and other microorganisms) often first gain access to crevices and spaces along or within the access system from environmental contamination, the healthcare worker, or from the skin or excretions of the patient. The bacteria often propagate in these crevices and spaces producing a protective biofilm. Often, portions of these residing bacteria, with or without supporting biofilm, can be displaced into the lumen of the access device. This displacement is commonly mechanical and induced by the insertion of a solid member such as a male luer into the device. Once displaced, the bacteria are then readily carried by the solid member or by fluid flow into the patient where they can cause death especially in patients with low white blood cell counts or internal prosthetic devices. Each time a conventional access device is entered from the outside the risk to the patient is increased. Typical access systems include, for example luer valves, ports, stopcocks, catheter and tubing mounted septum, hollow receivers, introducers, catheters, manifolds, hubs with extension sets, and open tubing connection systems to name a few. The term access systems is extended herein to include systems which receive a medical implement and which contain medical agents for insertion into a patient or for receipt of fluid from within a patient body such as drug vials, IV bags, pressure monitoring systems, and urinary bags to name a few. Access systems generally have interior portions for receiving medical implements, for example male luers, needles, biopsy devices, retrieval devices, catheters, and stents to name a few. Access systems also usually include at least one interior lumen to receive fluid or to store fluid.
In an example, access systems which comprise the luer receiving hubs of IV catheters and Y sites are particularly vulnerable because they may be entered with external male luers up to 10 or more times a day. Often the luer is contaminated during use but this contamination is invisible so that the luer is stored in a cap and reused. Research performed at the Center for Disease Control and Prevention clearly demonstrated that piston luer valves have internal walls, which can allow growth of vast numbers of deadly bacteria.
FIG. 1 shows a piston luer valve of the prior art with the exposed circumferential crevice into which bacteria can gain access to a region of incubation. The straight arrow points to the circumferential crevice at the face of the device, which connects directly with the internal walls of the valve (curved arrow). FIG. 3 is a photo of a pair of piston luer valves of the prior art, showing how the male luer is connected to the upper face of the piston luer valve (region of both the straight and curved arrow of FIG. 1). Once the bacteria gain access the inner surface of the piston luer valves biofilm can attach to the inner surface. To illustrate, FIG. 3 is an electron micrograph of bacteria and biofilm on the inner surface of a piston luer valve of FIG. 2 taken during a study by the Centers for Disease Control and Prevention in Atlanta Ga., (Donlan et al., Journal of Clinical Microbiology, February 2001, p. 750-753, Vol. 39, No. 2.). The article is incorporated herein by reference and provides additional background for the present invention.
The problem with at least some of the piston luer valves has become an increasingly recognized problem with published outbreaks. Indeed, when a patient in 2006 with an indwelling IV catheter develops a fever, the physician must promptly consider the piston luer valve as the potential source of the infection and replace it if there is any question as to whether or not the luer valve has been colonized internally.
Another problem relates to contamination and/or colonization of implements (such as the luer tip) between insertions into the access device. For example, during intermittent piggyback infusions, it is desirable to store the male luer in a sterile environment between uses. The problems associated with the storage of medical implements between uses are also discussed in U.S. Pat. No. 5,167,643 of the present inventor (the contents of which are incorporated by reference as if completely disclosed herein). This patent provides additional background for the present invention. Although capping and docking the luer tip can provide a component of protection from the environment, the tip end and outer sidewall of the male luer is often already contaminated with bacteria before recapping therefore the cap can actually act as an incubator. Bacteria actually can reach the luer tip from the access device itself. In fact, during use, the tip (including the outer sidewall of the tip) of the male luer as in FIG. 2 actually resides within the previously discussed circumferential crevice and adjacent the sidewall (FIG. 1) of the piston luer valve.
The present inventor has witnessed marked visible contamination of a luer tip, which was withdrawn from a open piston luer valve of the type shown in FIG. 2 in use in the intensive care unit. If this contamination had not been visible and the male luer stored in a conventional cap, this contamination might well have been displaced into the patient with the next connection. Most of the time the contaminating microorganisms are not associated with visible biofilm. So that the organisms are commonly carried directly into the caps and/or valve where they can proliferate and cause death.
Indeed, both the biofilm and the bacteria within the circumferential crevice can become attached to the male luer tip and then be carried to the site of storage (such as within a new sterile cap). In this case the interior of the new cap will now become contaminated by the outside of the male luer and the organisms can then propagate on the male luer tip and within the cap between accesses. Since caps are commonly reused and may contain fluid from the luer, the cap, which is supposed to act as a “luer protector”, can actually function as an incubator for bacteria during and between connections with the access device. As is evident from this discussion, the problem is profound because the system interconnects between the implement, the cover for the implement, and the access device. Once a reservoir for bacterial growth is allowed to develop within an access device, the cover, or the medical implement itself, the organism can produce a trail of contaminating movement to all connecting components of the system.
As discussed in U.S. Pat. No. 6,171,287 of the present inventor (the contents of which are incorporated by reference as if completely disclosed herein), structural complexity as a function of spaces between internal moving parts, and especially exposed crevices which connect to internal rigid components can greatly increase the risk of colonization. However, even with the elimination of these crevices, bacteria can still invade access systems. One approach has been to add an anti-infective chemical agent to access devices as coatings, impregnations, or filling fluid. However this approach is often less than optimally effective because biofilm, indwelling fluid, or distance may protect the organism from diffusion of the agent. Also the bacteria or yeast may develop resistance to the chemical agent or the patient or an incompatible drug may react to the agent. Another approach commonly is to increase the education of the need to scrub the surface with disinfectant. Unfortunately, as is evident from a review of FIG. 1, the circumferential crevice of piston luer valves of the type discussed above is not accessible to scrubbing. Many of these types of devices are manufactured with opaque outer sidewalls hiding the circumferential crevice so even the presence of blood and other nutrients within the crevice are not visible to the healthcare worker. The outside of the device may be scrubbed and look pristine while the inside is loaded with nutrients and bacteria, which the healthcare worker cannot see. Furthermore, this approach is unreliable as the healthcare worker may be distracted, or operating in an emergent environment with other priorities. The education approach does not solve the inherent weakness of the access device and places the health of the patient at the mercy of the unpredictable diligence of the potentially highly distracted healthcare worker.
One of the primary problems associated with access devices such as the luer valve is the failure of healthcare workers to scrub or otherwise prep the surface of the septum. At the least, healthcare workers would benefit from a reminder to scrub the surface before accessing the valve.
One embodiment of the present invention comprises a connection system comprising; a elastomeric septum defining an outer face, a cannula, which can be a male luer, having a distal end and defining at least one distal opening for flowing fluid out of the cannula, the opening defining at least one wall side wall facing the opening, the opening and the septum face being configured to minimize the contact of side wall with the septum face to minimize the potential transfer of microorganisms to the inner wall. The opening and the septum face can be configured such that the septum face does not engage the inner wall of the opening.
One embodiment of the present invention comprises a method for testing the cannula and septum system described above comprising; configuring at least one of a septum and a cannula such that the cannula can penetrate at least partially through the septum with reduced contact between the septum face and the opening, penetrating the septum with the cannula, testing at least one of the cannula and septum for the present of residual microorganisms which have passed at least partially through the septum during the penetration, modifying the configuration of at least one of a septum and a cannula to reduce the presence of residual microorganisms, and repeating at lest steps a through c. An embodiment further comprises the step of adjusting the compression of the septum prior to the penetrating step. An embodiment further comprises the step of adjusting the durometer of the septum prior to the penetrating step. An embodiment further comprises the step of adjusting the composition of the septum prior to the penetrating step. An embodiment further comprises the step of adjusting the elastic modulus of the septum prior to the penetrating step. An embodiment further comprises the step of adjusting the composition of the septum prior to the penetrating step. An embodiment further comprises the step of adjusting the surface texture of the septum prior to the penetrating step. An embodiment further comprises the step of adjusting the shape of the face of the septum prior to the penetrating step. An embodiment further comprises the step of adjusting the shape of the opening of the cannula prior to the penetrating step. An embodiment further comprises the step of adjusting the angle of contact between the tip of the cannula or the opening prior to the penetrating step.
It is the purpose of the present invention to provide a system and method, which reminds the healthcare worker to clean the access device before accessing it.
It is the purpose of the present invention to provide a system and method, which provides a chemical agent which functions synergistically with a solid fluid wave to achieve mechanical elimination of bacteria during the insertion, retention, and/or withdrawal of an implement into and from an access device.
It is the purpose of the present invention to provide a system and method for developing medical devices, which achieve optimal mechanical elimination of bacteria during the insertion of an implement into an access device to reduce the dependence on the chemical elimination of bacteria.
It is the purpose of the present invention to provide a system and method which generates a comprehensive solid fluid wave to displace and/or destroy bacteria from the exposed portion of a medical implement which is inserted into an access device.
It is the purpose of the present invention to provide a system and method, which provides an outer face which is specifically shaped with internally projecting elastomeric walls (which can be a tube) to match the shape of the leading end of a tubular medical implement during insertion, such that a solid fluid wave derived of the elastomeric face is applied circumferentially to the leading end to eliminate bacteria from the leading end.
It is the purpose of the present invention to provide a system and method, which is designed to mechanically kill bacteria on medical access devices during the insertion of an implement into the access device using a highly flexible mechanical force, which overcomes both the flexibility and hiding defenses of bacteria.
It is the purpose of the present invention to provide a system and method, which is designed to kill bacteria carried by a medical implement by directed, forceful application of an elastomer against the implement during insertion of the implement into and/or through the access device.
It is the purpose of the present invention to provide a system and method, which is designed to specifically eliminate bacteria within an access device by combined chemical action and mechanical force against the bacterial cell wall.
It is the purpose of the present invention to provide a system and method, which is designed to provide an inexpensive valve cover which can provide this enhanced protection for a cost which does not greatly exceed the cost of the conventional prepackaged chlorhexidine disinfectant swab itself.
It is the purpose of the present invention to provide a system and method, which is designed to specifically kill bacteria within an access device by combined chemical action and mechanical compression to force the chemical agent into compressed juxtaposition with the cell walls of the bacteria to increase the exposure of the sacculus to the chemical agent.
It is the purpose of the present invention to provide a system and method, which is designed to specifically kill bacteria within an access device by combining a chemical agent with an elastomer and then by mechanically compressing the elastomer against a medical implement to increase at least the proximity and/or the release of the chemical agent to target bacteria on the implement.
It is the purpose of the present invention to provide a soft elastomer mounted within a rigid or elastic housing wherein the elastomer and housing are configured such that insertion of an implement against the elastomer causes enclosed compression of the elastomer by the housing to produce a predictable fluidic dispersion of the elastomer and thereby producing a solid fluid wave against the implement such that the bacteria residing on the implement and/or the elastomer are destroyed or displaced.
It is another purpose of the present invention to provide a soft elastomeric slitted septum mounted within a rigid or elastic housing wherein the elastomer and housing are configured such that insertion of a male luer into the slit causes enclosed compression of the elastomer by the housing and against the male luer such that substantially all of the bacteria residing on the outside of the male luer are destroyed or wiped off.
It is the purpose of the present invention to provide a luer receiving septum with an upper face configured such that the outer edge of the circular end of the luer tip contacts the face first and deflects the face laterally so that the slit opens and the luer is advanced into the slit through the face with minimal or no forceful contact between the inner edge of circular end of the luer tip and the face to minimize the potential for the displacement of bacteria from the face to the inner edge of the luer.
It is the purpose of the present invention to provide a slitted luer receiving valve, which provides a tight resting compression force and which provides a release mechanism so that the compression force is releasable by an advancing male luer through the slit and wherein the force still provides a tight compression force against the wall of the advancing luer after the release so that the high compression force can tightly seal the resting slit and eliminate bacteria on the wall of the advancing luer so that the luer can be advanced through an area of tight resting compression with an insertion force which is less than would occur with a similar resting compression without the release mechanism.
It is the purpose of the present invention to provide a slitted elastomeric septum wherein the septum adjacent the slit is highly compressed by elastic supports (which supports can be elastomeric) which supports are at least partially collapsible releasing at least a portion of the compression over a short distance such that the high compression force is reestablished against the outer luer wall upon completion of the insertion of the luer into the slit.
It is further the purpose of the present invention to provide a luer-receiving valve, which also provides mitigation of negative pressure induced by withdrawal of the luer from the valve.
It is further the purpose of the present invention to provide a luer-receiving valve, which is capable of tight sealing about the luer for use with high-pressure injection.
It is further the purpose of the present invention to provide a luer-receiving valve or blunt cannula receiving system which a first slit (which can extend through the proximal face) with a long transverse axis extending along a first direction and a second slit (which can extend through the distal face) with a long transverse axis extending along a second direction, (which second direction can be perpendicular to the first direction) and wherein a first set of opposing slots can be provided aligned parallel to the first slit and a second set of opposing slots can be provided aligned parallel to the second slit.